Weight-reducing effects of the plasma protein encoded by the obese gene

The gene product of the ob locus is important in the regulation of body weight. The ob product was shown to be present as a 16-kilodalton protein in mouse and human plasma but was undetectable in plasma from C57BL/6J ob/ob mice. Plasma levels of this protein were increased in diabetic (db) mice, a mutant thought to be resistant to the effects of ob. Daily intraperitoneal injections of either mouse or human recombinant OB protein reduced the body weight of ob/ob mice by 30 percent after 2 weeks of treatment with no apparent toxicity but had no effect on db/db mice. The protein reduced food intake and increased energy expenditure in ob/ob mice. Injections of wild-type mice twice daily with the mouse protein resulted in a sustained 12 percent weight loss, decreased food intake, and a reduction of body fat from 12.2 to 0.7 percent. These data suggest that the OB protein serves an endocrine function to regulate body fat stores.

Effects of the obese gene product on body weight regulation in ob/ob mice

C57BL/6J mice with a mutation in the obese (ob) gene are obese, diabetic, and exhibit reduced activity, metabolism, and body temperature. Daily intraperitoneal injection of these mice with recombinant OB protein lowered their body weight, percent body fat, food intake, and serum concentrations of glucose and insulin. In addition, metabolic rate, body temperature, and activity levels were increased by this treatment. None of these parameters was altered beyond the level observed in lean controls, suggesting that the OB protein normalized the metabolic status of the ob/ob mice. Lean animals injected with OB protein maintained a smaller weight loss throughout the 28-day study and showed no changes in any of the metabolic parameters. These data suggest that the OB protein regulates body weight and fat deposition through effects on metabolism and appetite.

Once-Weekly Semaglutide in Adults with Overweight or Obesity

BACKGROUND

Obesity is a global health challenge with few pharmacologic options. Whether adults with obesity can achieve weight loss with once-weekly semaglutide at a dose of 2.4 mg as an adjunct to lifestyle intervention has not been confirmed.

METHODS

In this double-blind trial, we enrolled 1961 adults with a body-mass index (the weight in kilograms divided by the square of the height in meters) of 30 or greater (≥27 in persons with ≥1 weight-related coexisting condition), who did not have diabetes, and randomly assigned them, in a 2:1 ratio, to 68 weeks of treatment with once-weekly subcutaneous semaglutide (at a dose of 2.4 mg) or placebo, plus lifestyle intervention. The coprimary end points were the percentage change in body weight and weight reduction of at least 5%. The primary estimand (a precise description of the treatment effect reflecting the objective of the clinical trial) assessed effects regardless of treatment discontinuation or rescue interventions.

RESULTS

The mean change in body weight from baseline to week 68 was -14.9% in the semaglutide group as compared with -2.4% with placebo, for an estimated treatment difference of -12.4 percentage points (95% confidence interval [CI], -13.4 to -11.5; P<0.001). More participants in the semaglutide group than in the placebo group achieved weight reductions of 5% or more (1047 participants [86.4%] vs. 182 [31.5%]), 10% or more (838 [69.1%] vs. 69 [12.0%]), and 15% or more (612 [50.5%] vs. 28 [4.9%]) at week 68 (P<0.001 for all three comparisons of odds). The change in body weight from baseline to week 68 was -15.3 kg in the semaglutide group as compared with -2.6 kg in the placebo group (estimated treatment difference, -12.7 kg; 95% CI, -13.7 to -11.7). Participants who received semaglutide had a greater improvement with respect to cardiometabolic risk factors and a greater increase in participant-reported physical functioning from baseline than those who received placebo. Nausea and diarrhea were the most common adverse events with semaglutide; they were typically transient and mild-to-moderate in severity and subsided with time. More participants in the semaglutide group than in the placebo group discontinued treatment owing to gastrointestinal events (59 [4.5%] vs. 5 [0.8%]).

CONCLUSIONS

In participants with overweight or obesity, 2.4 mg of semaglutide once weekly plus lifestyle intervention was associated with sustained, clinically relevant reduction in body weight. (Funded by Novo Nordisk; STEP 1 ClinicalTrials.gov number, NCT03548935).

Effects of human growth hormone in men over 60 years old

BACKGROUND

The declining activity of the growth hormone--insulin-like growth factor I (IGF-I) axis with advancing age may contribute to the decrease in lean body mass and the increase in mass of adipose tissue that occur with aging.

METHODS

To test this hypothesis, we studied 21 healthy men from 61 to 81 years old who had plasma IGF-I concentrations of less than 350 U per liter during a six-month base-line period and a six-month treatment period that followed. During the treatment period, 12 men (group 1) received approximately 0.03 mg of biosynthetic human growth hormone per kilogram of body weight subcutaneously three times a week, and 9 men (group 2) received no treatment. Plasma IGF-I levels were measured monthly. At the end of each period we measured lean body mass, the mass of adipose tissue, skin thickness (epidermis plus dermis), and bone density at nine skeletal sites.

RESULTS

In group 1, the mean plasma IGF-I level rose into the youthful range of 500 to 1500 U per liter during treatment, whereas in group 2 it remained below 350 U per liter. The administration of human growth hormone for six months in group 1 was accompanied by an 8.8 percent increase in lean body mass, a 14.4 percent decrease in adipose-tissue mass, and a 1.6 percent increase in average lumbar vertebral bone density (P less than 0.05 in each instance). Skin thickness increased 7.1 percent (P = 0.07). There was no significant change in the bone density of the radius or proximal femur. In group 2 there was no significant change in lean body mass, the mass of adipose tissue, skin thickness, or bone density during treatment.

CONCLUSIONS

Diminished secretion of growth hormone is responsible in part for the decrease of lean body mass, the expansion of adipose-tissue mass, and the thinning of the skin that occur in old age.

The effects of treatment with recombinant human growth hormone on body composition and metabolism in adults with growth hormone deficiency

In a double-blind, placebo-controlled trial, we studied the effects of six months of growth hormone replacement in 24 adults with growth hormone deficiency. Most of the patients had acquired growth hormone deficiency during adulthood as a consequence of treatment for pituitary tumors, and all were receiving appropriate thyroid, adrenal, and gonadal hormone replacement. The daily dose of recombinant human growth hormone (rhGH) was 0.07 U per kilogram of body weight, given subcutaneously at bedtime. The mean (+/- SE) plasma concentration of insulin-like growth factor I increased from 0.41 +/- 0.05 to 1.53 +/- 0.16 U per liter during rhGH treatment. Treatment with rhGH had no effect on body weight. The mean lean body mass, however, increased by 5.5 +/- 1.1 kg (P less than 0.0001), and the fat mass decreased by 5.7 +/- 0.9 kg (P less than 0.0001) in the group treated with growth hormone; neither changed significantly in the placebo group. The basal metabolic rate, measured at base line and after one and six months of rhGH administration, increased significantly; the respective values were 32.4 +/- 1.4, 37.2 +/- 2.2, and 34.4 +/- 1.6 kcal per kilogram of lean body mass per day (P less than 0.001 for both comparisons). Fasting plasma cholesterol levels were lower (P less than 0.05) in the rhGH-treated group than in the placebo group, whereas plasma triglyceride values were similar in the two groups throughout the study. We conclude that growth hormone has a role in the regulation of body composition in adults, probably through its anabolic and lipolytic actions.

Ghrelin causes hyperphagia and obesity in rats

Ghrelin, a circulating growth hormone-releasing peptide derived from the stomach, stimulates food intake. The lowest systemically effective orexigenic dose of ghrelin was investigated and the resulting plasma ghrelin concentration was compared with that during fasting. The lowest dose of ghrelin that produced a significant stimulation of feeding after intraperitoneal injection was 1 nmol. The plasma ghrelin concentration after intraperitoneal injection of 1 nmol of ghrelin (2.83 +/- 0.13 pmol/ml at 60 min postinjection) was not significantly different from that occurring after a 24-h fast (2.79 +/- 0.32 pmol/ml). After microinjection into defined hypothalamic sites, ghrelin (30 pmol) stimulated food intake most markedly in the arcuate nucleus (Arc) (0-1 h food intake, 427 +/- 43% of control; P < 0.001 vs. control, P < 0.01 vs. all other nuclei), which is potentially accessible to the circulation. After chronic systemic or intracerebroventricular (ICV) administration of ghrelin for 7 days, cumulative food intake was increased (intraperitoneal ghrelin 13.6 +/- 3.4 g greater than saline-treated, P < 0.01; ICV ghrelin 19.6 +/- 5.5 g greater than saline-treated, P < 0.05). This was associated with excess weight gain (intraperitoneal ghrelin 21.7 +/- 1.4 g vs. saline 10.6 +/- 1.9 g, P < 0.001; ICV ghrelin 15.3 +/- 4.3 g vs. saline 2.2 +/- 3.8 g, P < 0.05) and adiposity. These data provide evidence that ghrelin is important in long-term control of food intake and body weight and that circulating ghrelin at fasting concentrations may stimulate food intake.

Effect of conjugated linoleic acid on body composition in mice

The effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing 5.5% corn oil or a CLA-supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA-supplemented diet exhibited 57% and 60% lower body fat and 5% and 14% increased lean body mass relative to controls (P < 0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3-L1 adipocytes CLA treatment (1 x 10(-4)M) significantly reduced heparin-releasable lipoprotein lipase activity (-66%) and the intracellular concentrations of triacylglyceride (-8%) and glycerol (-15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P < 0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.

Metabolic effects of metformin in non-insulin-dependent diabetes mellitus

BACKGROUND

The metabolic effects and mechanism of action of metformin are still poorly understood, despite the fact that it has been used to treat patients with non-insulin-dependent diabetes mellitus (NIDDM) for more than 30 years.

METHODS

In 10 obese patients with NIDDM, we used a combination of isotope dilution, indirect calorimetry, bioimpedance, and tissue-balance techniques to assess the effects of metformin on systemic lactate, glucose, and free-fatty-acid turnover; lactate oxidation and the conversion of lactate to glucose; skeletal-muscle glucose and lactate metabolism; body composition; and energy expenditure before and after four months of treatment.

RESULTS

Metformin treatment decreased the mean (+/- SD) glycosylated hemoglobin value from 13.2 +/- 2.2 percent to 10.5 +/- 1.6 percent (P < 0.001) and reduced fasting plasma glucose concentrations from 220 +/- 41 to 155 +/- 28 mg per deciliter (12.2 +/- 0.7 to 8.6 +/- 0.5 mmol per liter) (P < 0.001). Although resting energy expenditure did not change, the patients lost 2.7 +/- 1.3 kg of weight (P < 0.001), 88 percent of which was adipose tissue. The mean (+/- SE) rate of plasma glucose turnover (hepatic glucose output and systemic glucose disposal) decreased from 2.8 +/- 0.2 to 2.0 +/- 0.2 mg per kilogram of body weight per minute (15.3 +/- 0.9 to 10.8 +/- 0.9 mumol per kilogram per minute) (P < 0.001), as a result of a decrease in hepatic glucose output; systemic glucose clearance did not change. The rate of conversion of lactate to glucose (gluconeogenesis) decreased by 37 percent (P < 0.001), whereas lactate oxidation increased by 25 percent (P < 0.001). There were no changes in the plasma lactate concentration, plasma lactate turnover, muscle lactate release, plasma free-fatty-acid turnover, or uptake of glucose by muscle.

CONCLUSIONS

Metformin acts primarily by decreasing hepatic glucose output, largely by inhibiting gluconeogenesis. It also seems to induce weight loss, preferentially involving adipose tissue.

Cardiometabolic risk of second-generation antipsychotic medications during first-time use in children and adolescents

CONTEXT

Cardiometabolic effects of second-generation antipsychotic medications are concerning but have not been sufficiently studied in pediatric and adolescent patients naive to antipsychotic medication.

OBJECTIVE

To study the association of second-generation antipsychotic medications with body composition and metabolic parameters in patients without prior antipsychotic medication exposure.

DESIGN, SETTING, AND PATIENTS

Nonrandomized Second-Generation Antipsychotic Treatment Indications, Effectiveness and Tolerability in Youth (SATIETY) cohort study, conducted between December 2001 and September 2007 at semi-urban, tertiary care, academic inpatient and outpatient clinics in Queens, New York, with a catchment area of 4.5-million individuals. Of 505 youth aged 4 to 19 years with 1 week or less of antipsychotic medication exposure, 338 were enrolled (66.9%). Of these patients, 272 had at least 1 postbaseline assessment (80.5%), and 205 patients [corrected] completed the study (60.7%). Patients had mood spectrum (n = 130; 47.8%), schizophrenia spectrum (n = 82; 30.1%), and disruptive or aggressive behavior spectrum (n = 60; 22.1%) disorders. Fifteen patients who refused participation or were nonadherent served as a comparison group.

INTERVENTION

Treatment with aripiprazole, olanzapine, quetiapine, or risperidone for 12 weeks.

MAIN OUTCOME MEASURES

Weight gain and changes in lipid and metabolic parameters.

RESULTS

After a median of 10.8 weeks (interquartile range, 10.5-11.2 weeks) of treatment, weight increased by 8.5 kg (95% confidence interval [CI], 7.4 to 9.7 kg) with olanzapine (n = 45), by 6.1 kg (95% CI, 4.9 to 7.2 kg) with quetiapine (n = 36), by 5.3 kg (95% CI, 4.8 to 5.9 kg) with risperidone (n = 135), and by 4.4 kg (95% CI, 3.7 to 5.2 kg) with aripiprazole (n = 41) compared with the minimal weight change of 0.2 kg (95% CI, -1.0 to 1.4 kg) in the untreated comparison group (n = 15). With olanzapine and quetiapine, respectively, mean levels increased significantly for total cholesterol (15.6 mg/dL [95% CI, 6.9 to 24.3 mg/dL] P < .001 and 9.1 mg/dL [95% CI, 0.4 to 17.7 mg/dL] P = .046), triglycerides (24.3 mg/dL [95% CI, 9.8 to 38.9 mg/dL] P = .002 and 37.0 mg/dL [95% CI, 10.1 to 63.8 mg/dL] P = .01), non-high-density lipoprotein (HDL) cholesterol (16.8 mg/dL [95% CI, 9.3 to 24.3 mg/dL] P < .001 and 9.9 mg/dL [95% CI, 1.4 to 18.4 mg/dL] P = .03), and ratio of triglycerides to HDL cholesterol (0.6 [95% CI, 0.2 to 0.9] P = .002 and (1.2 [95% CI, 0.4 to 2.0] P = .004). With risperidone, triglycerides increased significantly (mean level, 9.7 mg/dL [95% CI, 0.5 to 19.0 mg/dL]; P = .04). Metabolic baseline-to-end-point changes were not significant with aripiprazole or in the untreated comparison group.

CONCLUSIONS

First-time second-generation antipsychotic medication use was associated with significant weight gain with each medication. Metabolic changes varied among the 4 antipsychotic medications.

The ratio of macronutrients, not caloric intake, dictates cardiometabolic health, aging, and longevity in ad libitum-fed mice

The fundamental questions of what represents a macronutritionally balanced diet and how this maintains health and longevity remain unanswered. Here, the Geometric Framework, a state-space nutritional modeling method, was used to measure interactive effects of dietary energy, protein, fat, and carbohydrate on food intake, cardiometabolic phenotype, and longevity in mice fed one of 25 diets ad libitum. Food intake was regulated primarily by protein and carbohydrate content. Longevity and health were optimized when protein was replaced with carbohydrate to limit compensatory feeding for protein and suppress protein intake. These consequences are associated with hepatic mammalian target of rapamycin (mTOR) activation and mitochondrial function and, in turn, related to circulating branched-chain amino acids and glucose. Calorie restriction achieved by high-protein diets or dietary dilution had no beneficial effects on lifespan. The results suggest that longevity can be extended in ad libitum-fed animals by manipulating the ratio of macronutrients to inhibit mTOR activation.

Leptin directly activates SF1 neurons in the VMH, and this action by leptin is required for normal body-weight homeostasis

Leptin, an adipocyte-derived hormone, acts directly on the brain to control food intake and energy expenditure. An important question is the identity of first-order neurons initiating leptin's anti-obesity effects. A widely held view is that most, if not all, of leptin's effects are mediated by neurons located in the arcuate nucleus of the hypothalamus. However, leptin receptors (LEPRs) are expressed in other sites as well, including the ventromedial hypothalamus (VMH). The possible role of leptin acting in "nonarcuate" sites has largely been ignored. In the present study, we show that leptin depolarizes and increases the firing rate of steroidogenic factor-1 (SF1)-positive neurons in the VMH. We also show, by generating mice that lack LEPRs on SF1-positive neurons, that leptin action at this site plays an important role in reducing body weight and, of note, in resisting diet-induced obesity. These results reveal a critical role for leptin action on VMH neurons.

Adipose tissue mass can be regulated through the vasculature

Tumor growth is angiogenesis dependent. We hypothesized that nonneoplastic tissue growth also depends on neovascularization. We chose adipose tissue as an experimental system because of its remodeling capacity. Mice from different obesity models received anti-angiogenic agents. Treatment resulted in dose-dependent, reversible weight reduction and adipose tissue loss. Marked vascular remodeling was evident in adipose tissue sections, which revealed decreased endothelial proliferation and increased apoptosis in treated mice compared with controls. Continuous treatment maintained mice near normal body weights for age without adverse effects. Metabolic adaptations in food intake, metabolic rate, and energy substrate utilization were associated with anti-angiogenic weight loss. We conclude that adipose tissue mass is sensitive to angiogenesis inhibitors and can be regulated by its vasculature.

Testosterone dose-response relationships in healthy young men

Testosterone increases muscle mass and strength and regulates other physiological processes, but we do not know whether testosterone effects are dose dependent and whether dose requirements for maintaining various androgen-dependent processes are similar. To determine the effects of graded doses of testosterone on body composition, muscle size, strength, power, sexual and cognitive functions, prostate-specific antigen (PSA), plasma lipids, hemoglobin, and insulin-like growth factor I (IGF-I) levels, 61 eugonadal men, 18-35 yr, were randomized to one of five groups to receive monthly injections of a long-acting gonadotropin-releasing hormone (GnRH) agonist, to suppress endogenous testosterone secretion, and weekly injections of 25, 50, 125, 300, or 600 mg of testosterone enanthate for 20 wk. Energy and protein intakes were standardized. The administration of the GnRH agonist plus graded doses of testosterone resulted in mean nadir testosterone concentrations of 253, 306, 542, 1,345, and 2,370 ng/dl at the 25-, 50-, 125-, 300-, and 600-mg doses, respectively. Fat-free mass increased dose dependently in men receiving 125, 300, or 600 mg of testosterone weekly (change +3.4, 5.2, and 7.9 kg, respectively). The changes in fat-free mass were highly dependent on testosterone dose (P = 0.0001) and correlated with log testosterone concentrations (r = 0.73, P = 0.0001). Changes in leg press strength, leg power, thigh and quadriceps muscle volumes, hemoglobin, and IGF-I were positively correlated with testosterone concentrations, whereas changes in fat mass and plasma high-density lipoprotein (HDL) cholesterol were negatively correlated. Sexual function, visual-spatial cognition and mood, and PSA levels did not change significantly at any dose. We conclude that changes in circulating testosterone concentrations, induced by GnRH agonist and testosterone administration, are associated with testosterone dose- and concentration-dependent changes in fat-free mass, muscle size, strength and power, fat mass, hemoglobin, HDL cholesterol, and IGF-I levels, in conformity with a single linear dose-response relationship. However, different androgen-dependent processes have different testosterone dose-response relationships.

Cachectin/tumor necrosis factor induces cachexia, anemia, and inflammation

Cachexia is a potentially lethal syndrome of unknown etiology characterized by anorexia, weight loss, and protein wasting that frequently complicates the treatment of chronic inflammation and cancer. Cachectin/TNF was isolated during the search for a humoral mediator of cachexia and found to stimulate the breakdown of energy stores from adipocytes and myocytes in vitro, but the chronic effects of the monokine in vivo are not known. Sublethal doses of recombinant human cachectin administered twice daily for 7-10 d caused cachexia in rats, as evidenced by reduced food intake, weight loss, and depletion of whole-body lipid and protein stores. Significant anemia is also observed and found to be the result of decreased red blood cell mass, not expanded plasma volume. Leukocytosis and histopathological evidence of tissue injury and inflammation are observed in several organs, including omentum, liver, spleen, and heart. These data suggests that the exposure of the normal host to cachectin is capable of inducing a pathophysiological syndrome of cachexia, anemia, and inflammation similar to that observed during inflammatory states or malignancy.

Evidence that the trans-10,cis-12 isomer of conjugated linoleic acid induces body composition changes in mice

We investigated the effects of conjugated linoleic acid (CLA) preparations, which were enriched for the cis-9,trans-11 CLA isomer or the trans-10,cis-12 CLA isomer, on body composition in mice. Body composition changes (reduced body fat, enhanced body water, enhanced body protein, and enhanced body ash) were associated with feeding the trans-10,cis-12 CLA isomer. In cultured 3T3-L1 adipocytes, the trans-10,cis-12 isomer reduced lipoprotein lipase activity, intracellular triacylglycerol and glycerol, and enhanced glycerol release into the medium. By contrast, the cis-9,trans-11 and trans-9,trans-11 CLA isomers did not affect these biochemical activities. We conclude that CLA-associated body composition change results from feeding the trans-10,cis-12 isomer.

Dietary Polyphenols Promote Growth of the Gut Bacterium Akkermansia muciniphila and Attenuate High-Fat Diet-Induced Metabolic Syndrome

Dietary polyphenols protect against metabolic syndrome, despite limited absorption and digestion, raising questions about their mechanism of action. We hypothesized that one mechanism may involve the gut microbiota. To test this hypothesis, C57BL/6J mice were fed a high-fat diet (HFD) containing 1% Concord grape polyphenols (GP). Relative to vehicle controls, GP attenuated several effects of HFD feeding, including weight gain, adiposity, serum inflammatory markers (tumor necrosis factor [TNF]α, interleukin [IL]-6, and lipopolysaccharide), and glucose intolerance. GP lowered intestinal expression of inflammatory markers (TNFα, IL-6, inducible nitric oxide synthase) and a gene for glucose absorption (Glut2). GP increased intestinal expression of genes involved in barrier function (occludin) and limiting triglyceride storage (fasting-induced adipocyte factor). GP also increased intestinal gene expression of proglucagon, a precursor of proteins that promote insulin production and gut barrier integrity. 16S rRNA gene sequencing and quantitative PCR of cecal and fecal samples demonstrated that GP dramatically increased the growth of Akkermansia muciniphila and decreased the proportion of Firmicutes to Bacteroidetes, consistent with prior reports that similar changes in microbial community structure can protect from diet-induced obesity and metabolic disease. These data suggest that GP act in the intestine to modify gut microbial community structure, resulting in lower intestinal and systemic inflammation and improved metabolic outcomes. The gut microbiota may thus provide the missing link in the mechanism of action of poorly absorbed dietary polyphenols.

Effects of Androgenic-Anabolic Steroids in Athletes

Androgenic-anabolic steroids (AAS) are synthetic derivatives of the male hormone testosterone. They can exert strong effects on the human body that may be beneficial for athletic performance. A review of the literature revealed that most laboratory studies did not investigate the actual doses of AAS currently abused in the field. Therefore, those studies may not reflect the actual (adverse) effects of steroids. The available scientific literature describes that short-term administration of these drugs by athletes can increase strength and bodyweight. Strength gains of about 5-20% of the initial strength and increments of 2-5 kg bodyweight, that may be attributed to an increase of the lean body mass, have been observed. A reduction of fat mass does not seem to occur. Although AAS administration may affect erythropoiesis and blood haemoglobin concentrations, no effect on endurance performance was observed. Little data about the effects of AAS on metabolic responses during exercise training and recovery are available and, therefore, do not allow firm conclusions. The main untoward effects of short- and long-term AAS abuse that male athletes most often self-report are an increase in sexual drive, the occurrence of acne vulgaris, increased body hair and increment of aggressive behaviour. AAS administration will disturb the regular endogenous production of testosterone and gonadotrophins that may persist for months after drug withdrawal. Cardiovascular risk factors may undergo deleterious alterations, including elevation of blood pressure and depression of serum high-density lipoprotein (HDL)-, HDL2- and HDL3-cholesterol levels. In echocardiographic studies in male athletes, AAS did not seem to affect cardiac structure and function, although in animal studies these drugs have been observed to exert hazardous effects on heart structure and function. In studies of athletes, AAS were not found to damage the liver. Psyche and behaviour seem to be strongly affected by AAS. Generally, AAS seem to induce increments of aggression and hostility. Mood disturbances (e.g. depression, [hypo-]mania, psychotic features) are likely to be dose and drug dependent. AAS dependence or withdrawal effects (such as depression) seem to occur only in a small number of AAS users. Dissatisfaction with the body and low self-esteem may lead to the so-called 'reverse anorexia syndrome' that predisposes to the start of AAS use. Many other adverse effects have been associated with AAS misuse, including disturbance of endocrine and immune function, alterations of sebaceous system and skin, changes of haemostatic system and urogenital tract. One has to keep in mind that the scientific data may underestimate the actual untoward effects because of the relatively low doses administered in those studies, since they do not approximate doses used by illicit steroid users. The mechanism of action of AAS may differ between compounds because of variations in the steroid molecule and affinity to androgen receptors. Several pathways of action have been recognised. The enzyme 5-alpha-reductase seems to play an important role by converting AAS into dihydrotestosterone (androstanolone) that acts in the cell nucleus of target organs, such as male accessory glands, skin and prostate. Other mechanisms comprises mediation by the enzyme aromatase that converts AAS in female sex hormones (estradiol and estrone), antagonistic action to estrogens and a competitive antagonism to the glucocorticoid receptors. Furthermore, AAS stimulate erythropoietin synthesis and red cell production as well as bone formation but counteract bone breakdown. The effects on the cardiovascular system are proposed to be mediated by the occurrence of AAS-induced atherosclerosis (due to unfavourable influence on serum lipids and lipoproteins), thrombosis, vasospasm or direct injury to vessel walls, or may be ascribed to a combination of the different mechanisms. AAS-induced increment of muscle tissue can be attributed to hypertrophy and the formation of new muscle fibres, in which key roles are played by satellite cell number and ultrastructure, androgen receptors and myonuclei.

Effects of testosterone on body composition, bone metabolism and serum lipid profile in middle-aged men: a meta-analysis

OBJECTIVES

Ageing in men is associated with a gradual decline in serum testosterone levels and a concomitant loss of muscle mass, accumulation of central adiposity, impaired mobility and increased risk of bone fractures. Whether androgen treatment might be beneficial in these subjects is still under debate. We have carried out a systematic review of randomized controlled trials (RCTs) evaluating the effects of testosterone (T) administration to middle-aged and ageing men on body composition, muscle strength, bone density, markers of bone metabolism and serum lipid profile.

DATA SOURCE

A comprehensive search of all published randomized clinical trials was performed using the MEDLINE, Cochrane Library, EMBASE and Current Contents databases.

REVIEW METHODS

Guided by prespecified criteria, software-assisted data abstraction and quality assessed by two independent reviewers, 29 RCTs were found to be eligible. For each investigated variable, we reported the results of pooled estimates of testosterone treatment using the random effect model of meta-analysis. Heterogeneity, reproducibility and consistency of the findings across studies were explored using sensitivity and meta-regression analysis.

RESULTS

Overall, 1,083 subjects were evaluated, 625 randomized to T, 427 to placebo and 31 to observation (control group). Weighted mean age was 64.5 years (range 49.9--77.6) and mean serum testosterone was 10.9 nmol/l (range 7.8--19). Testosterone treatment produced: (i) a reduction of 1.6 kg (CI: 2.5--0.6) of total body fat, corresponding to -6.2% (CI: 9.2--3.3) variation of initial body fat, (ii) an increase in fat free mass of 1.6 kg (CI: 0.6--2.6), corresponding to +2.7% (CI: 1.1--4.4) increase over baseline and (iii) no change in body weight. The effects of T on muscle strength were heterogeneous, showing a tendency towards improvement only at the leg/knee extension and handgrip of the dominant arm (pooled effect size=0.3 standard mean difference (SMD), CI: -0.0 to 0.6). Testosterone improved bone mineral density (BMD) at the lumbar spine by +3.7% (CI: 1.0--6.4%) compared to placebo, but not at the femoral neck, and produced a consistent reduction in bone resorption markers (pooled effect size = -0.6 SMD, CI: -1.0 to -0.2). Testosterone also reduced total cholesterol by 0.23 mmol/l (CI: -0.37 to -0.10), especially in men with lower baseline T concentrations, with no change in low density lipoprotein (LDL)-cholesterol. A significant reduction of high density lipoprotein (HDL)-cholesterol was found only in studies with higher mean T-values at baseline (-0.085 mmol/l, CI: -0.017 to -0.003). Sensitivity and meta-regression analysis revealed that the dose/type of T used, in particular the possibility of aromatization, explained the heterogeneity in findings observed on bone density and HDL-cholesterol among studies.

CONCLUSION

The present analysis provides an estimate of the average treatment effects of testosterone therapy in middle-aged men. Our findings are sufficiently strong to justify further interventional studies focused on alternative targets of androgenic treatment carrying more stringent clinical implications, in particular the cardiovascular, metabolic and neurological systems.

Effects of testosterone on muscle strength, physical function, body composition, and quality of life in intermediate-frail and frail elderly men: a randomized, double-blind, placebo-controlled study

CONTEXT

Physical frailty is associated with reduced muscle strength, impaired physical function, and quality of life. Testosterone (T) increases muscle mass and strength in hypogonadal patients. It is unclear whether T has similar effects in intermediate-frail and frail elderly men with low to borderline-low T.

OBJECTIVE

Our objective was to determine the effects of 6 months T treatment in intermediate-frail and frail elderly men, on muscle mass and strength, physical function, and quality of life.

DESIGN AND SETTING

We conducted a randomized, double-blind, placebo-controlled, parallel-group, single-center study.

PARTICIPANTS

PARTICIPANTS were community-dwelling intermediate-frail and frail elderly men at least 65 yr of age with a total T at or below 12 nmol/liter or free T at or below 250 pmol/liter.

METHODS

Two hundred seventy-four participants were randomized to transdermal T (50 mg/d) or placebo gel for 6 months. Outcome measures included muscle strength, lean and fat mass, physical function, and self-reported quality of life.

RESULTS

Isometric knee extension peak torque improved in the T group (vs. placebo at 6 months), adjusted difference was 8.6 (95% confidence interval, 1.3-16.0; P = 0.02) Newton-meters. Lean body mass increased and fat mass decreased significantly in the T group by 1.08 +/- 1.8 and 0.9 +/- 1.6 kg, respectively. Physical function improved among older and frailer men. Somatic and sexual symptom scores decreased with T treatment; adjusted difference was -1.2 (-2.4 to -0.04) and -1.3 (-2.5 to -0.2), respectively.

CONCLUSIONS

T treatment in intermediate-frail and frail elderly men with low to borderline-low T for 6 months may prevent age-associated loss of lower limb muscle strength and improve body composition, quality of life, and physical function. Further investigations are warranted to extend these results.

Changes in body composition during androgen deprivation therapy for prostate cancer

The aim of this study was to determine the effects of initial treatment with a GnRH agonist on body composition in asymptomatic men with nonmetastatic prostate cancer. Forty men with locally advanced, node-positive or biochemically recurrent prostate cancer, no radiographic evidence of metastases, and no prior androgen deprivation therapy were treated with leuprolide 3-month depot 22.5 mg im every 12 wk for 48 wk. The main outcome measures were percentage changes in weight, percentage fat body mass, percentage lean body mass, fat distribution, and muscle size after 48 wk. Thirty-two subjects were evaluable. Serum T concentrations decreased by 96.3% plus or minus 0.4% (P < 0.001). Weight increased by 2.4% plus or minus 0.8% (P = 0.005). Percentage fat body mass increased by 9.4% plus or minus 1.7% (P < 0.001), and percentage lean body mass decreased by 2.7% plus or minus 0.5% (P < 0.001). Cross-sectional areas of the abdomen and abdominal sc fat increased by 3.9% plus or minus 1.2% (P = 0.003) and 11.1% plus or minus 3.4% (P = 0.003), respectively. In contrast, the cross-sectional area of intraabdominal fat did not change significantly (P = 0.94). Cross-sectional paraspinal muscle area decreased by 3.2% plus or minus 1.3% (P = 0.02). GnRH agonists increase weight and percentage fat body mass and decrease percentage lean body mass and muscle size in men with nonmetastatic prostate cancer. Increased fatness resulted primarily from accumulation of sc rather than intraabdominal adipose tissue.

Long-term testosterone gel (AndroGel) treatment maintains beneficial effects on sexual function and mood, lean and fat mass, and bone mineral density in hypogonadal men

Transdermal testosterone (T) delivery represents an effective alternative to injectable androgens. We studied 163 hypogonadal men who applied 5, 7.5, or 10 g AndroGel (T gel) 1% CIII per day for up to 42 months. Efficacy data were presented in 123 subjects considered evaluable. Continuous AndroGel treatment normalized mean serum T and free T levels. Mean serum 5alpha-dihydrotestosterone concentrations and 5alpha-dihydrotestosterone/T ratio slightly increased, mean serum estradiol/T ratio doubled, and mean serum FSH and LH levels were suppressed by T replacement. Sexual function and mood parameters improved rapidly and were maintained throughout T treatment. Lean body mass increased (P = 0.0001) and fat mass decreased (P = 0.0001), and these changes were maintained with treatment but were not accompanied by significant increases in muscle strength. Increases in serum bone markers suggestive of increased bone formation were followed by gradual and progressive increases in bone mineral density more in the spine (P = 0.0001) than the hip (P = 0.0004). Mild local skin irritation occurred in 12 subjects, resulting in discontinuation in only one subject. Except for the anticipated increase in hematocrit and hemoglobin, there were no clinically significant changes in blood counts or biochemistry. In three subjects with elevated serum prostate-specific antigen, prostate biopsies showed cancer. We conclude that continued application of AndroGel resulted in beneficial effects similar to those with injectables and other transdermal preparations. This study was neither placebo controlled nor powered to determine the effects of T treatment on prostate cancer risk. Thus, monitoring for prostatic disease and assessment for erythrocytosis are strongly advised to reduce the risk of adverse events with T treatment of hypogonadal men.

Sucrose compared with artificial sweeteners: different effects on ad libitum food intake and body weight after 10 wk of supplementation in overweight subjects

BACKGROUND

The role of artificial sweeteners in body-weight regulation is still unclear.

OBJECTIVE

We investigated the effect of long-term supplementation with drinks and foods containing either sucrose or artificial sweeteners on ad libitum food intake and body weight in overweight subjects.

DESIGN

For 10 wk, overweight men and women consumed daily supplements of either sucrose [n = 21, body mass index (BMI; in kg/m(2)) = 28.0] or artificial sweeteners (n = 20, BMI = 27.6). On average, sucrose supplements provided 3.4 MJ and 152 g sucrose/d and sweetener supplements provided 1.0 MJ and 0 g sucrose/d.

RESULTS

After 10 wk, the sucrose group had increases in total energy (by 1.6 MJ/d), sucrose (to 28% of energy), and carbohydrate intakes and decreases in fat and protein intakes. The sweetener group had small but significant decreases in sucrose intake and energy density. Body weight and fat mass increased in the sucrose group (by 1.6 and 1.3 kg, respectively) and decreased in the sweetener group (by 1.0 and 0.3 kg, respectively); the between-group differences were significant at P < 0.001 (body weight) and P < 0.01 (fat mass). Systolic and diastolic blood pressure increased in the sucrose group (by 3.8 and 4.1 mm Hg, respectively) and decreased in the sweetener group (by 3.1 and 1.2 mm Hg, respectively).

CONCLUSIONS

Overweight subjects who consumed fairly large amounts of sucrose (28% of energy), mostly as beverages, had increased energy intake, body weight, fat mass, and blood pressure after 10 wk. These effects were not observed in a similar group of subjects who consumed artificial sweeteners.

DHEA in elderly women and DHEA or testosterone in elderly men

BACKGROUND

Dehydroepiandrosterone (DHEA) and testosterone are widely promoted as antiaging supplements, but the long-term benefits, as compared with potential harm, are unknown.

METHODS

We performed a 2-year, placebo-controlled, randomized, double-blind study involving 87 elderly men with low levels of the sulfated form of DHEA and bioavailable testosterone and 57 elderly women with low levels of sulfated DHEA. Among the men, 29 received DHEA, 27 received testosterone, and 31 received placebo. Among the women, 27 received DHEA and 30 received placebo. Outcome measures included physical performance, body composition, bone mineral density (BMD), glucose tolerance, and quality of life.

RESULTS

As compared with the change from baseline to 24 months in the placebo group, subjects who received DHEA for 2 years had an increase in plasma levels of sulfated DHEA by a median of 3.4 microg per milliliter (9.2 micromol per liter) in men and by 3.8 microg per milliliter (10.3 micromol per liter) in women. Among men who received testosterone, the level of bioavailable testosterone increased by a median of 30.4 ng per deciliter (1.1 nmol per liter), as compared with the change in the placebo group. A separate analysis of men and women showed no significant effect of DHEA on body-composition measurements. Neither hormone altered the peak volume of oxygen consumed per minute, muscle strength, or insulin sensitivity. Men who received testosterone had a slight increase in fat-free mass, and men in both treatment groups had an increase in BMD at the femoral neck. Women who received DHEA had an increase in BMD at the ultradistal radius. Neither treatment improved the quality of life or had major adverse effects.

CONCLUSIONS

Neither DHEA nor low-dose testosterone replacement in elderly people has physiologically relevant beneficial effects on body composition, physical performance, insulin sensitivity, or quality of life. (ClinicalTrials.gov number, NCT00254371 [ClinicalTrials.gov].).

Changes in weight, body composition, and factors influencing energy balance among premenopausal breast cancer patients receiving adjuvant chemotherapy

PURPOSE

Weight gain is a common problem among breast cancer patients who receive adjuvant chemotherapy (CT). We undertook a study to determine the causes of this energy imbalance.

PATIENTS AND METHODS

Factors related to energy balance were assessed at baseline (within 3 weeks of diagnosis) and throughout 1 year postdiagnosis among 53 premenopausal women with operable breast carcinoma. Thirty-six patients received CT and 17 received only localized treatment (LT). Measures included body composition (dual energy x-ray absorptiometry), resting energy expenditure (REE; indirect calorimetry), dietary intake (2-day dietary recalls and food frequency questionnaires) and physical activity (physical activity records).

RESULTS

Mean weight gain in the LT patients was 1.0 kg versus 2.1 kg in the CT group (P =.02). No significant differences between groups in trend over time were observed for REE and energy intake; however, a significant difference was noted for physical activity (P =.01). Several differences between groups in 1-year change scores were detected. The mean change (+/- SE) in LT versus CT groups and P values for uncontrolled/controlled (age, race, radiation therapy, baseline body mass index, and end point under consideration) analysis are as follows: percentage of body fat (-0.1 +/- 0.4 v +2.2 +/- 0.6%; P =.001/0.04); fat mass (+0.1 +/- 0.3 v +2.3 +/- 0.7 kg; P =.002/0.04); lean body mass (+0.8 +/- 0.2 v -0.4 +/- 0.3 kg; P =.02/0.30); and leg lean mass (+0.5 +/- 0.1 v -0.2 +/- 0.1 kg; P =.01/0.11).

CONCLUSION

These data do not support overeating as a cause of weight gain among breast cancer patients who receive CT. The data suggest, however, that CT-induced weight gain is distinctive and indicative of sarcopenic obesity (weight gain in the presence of lean tissue loss or absence of lean tissue gain). The development of sarcopenic obesity with evidence of reduced physical activity supports the need for interventions focused on exercise, especially resistance training in the lower body, to prevent weight gain.